If a train receives multiple detector messages stating "NO DEFECTS", what is the implication?

When a train receives multiple detector messages indicating "NO DEFECTS," it implies that all the systems monitoring the train's condition, such as axle temperatures, wheel alignments, and brake problems, are functioning within safe parameters. Consequently, it provides a strong assurance of the train's integrity and safety for continued operation.

This clears the train to proceed, but stating that it may proceed at a moderate speed recognizes the necessity of exercising caution while traveling, ensuring that the crew can remain vigilant even when no immediate defects have been detected. Proceeding at moderate speed allows the crew to respond to unforeseen circumstances while maintaining efficiency in their operations.

As for the other options, stopping immediately is unnecessary when no defects have been reported, and being cleared to proceed without restriction would not encapsulate the prudent approach of ensuring moderate speed, which is a standard practice in train operations. Likewise, submitting to extra inspections is not warranted given the positive outcomes indicated by the detector messages.